Supporting roller set for tiltable support of a rotary drum

ABSTRACT

The invention relates to a supporting roller set for tiltable, axially movable and rotatable support for a rotary drum which can be driven in rotation. It comprises two supporting rollers which lie symmetrically on both sides of a vertical longitudinal central plane of the rotary drum and are each mounted in two rotary bearings which are fixed on bedplate which is tiltably supported on a static foundation. In order to be able to achieve an optimal self-adjustment with easy action of each supporting roller, each bedplate is supported by way of two articulated bearings disposed at a transverse spacing from one another on the foundation, of which the inner articulated bearing is constructed in the form of a ball-and-socket bearing, whilst the outer articulated bearing forms a movable bearing and is supported on the foundation so as to be slidably movable about the central point of the ball of the inner articulated bearing.

The invention relates to a supporting roller set for tiltable, axiallymovable and rotatable support for a rotary drum which can be driven inrotation, such as a rotary kiln, rotary dryer and the like, according tothe preamble to claim 1.

In order that rotary drums with relatively large dimensions, not onlywith regard to the diameter but also with regard to the length, can bereliably supported or mounted, use is made—as is generally known—of atleast two supporting roller sets which are disposed at a correspondingaxial distance from one another. In the case of such rotary drums withlarge dimensions, such as for example rotary kilns, rotary dryers andthe like, it is not possible to avoid the occurrence, on the one hand,of certain inaccuracies of assembly and, on the other hand, of more orless great deformations and distortions of the appertaining drum shell,which manifest themselves particularly severely in the case of rotarydrums with a strong heat effect, as in the case of rotary kilns. Inpractical operation this leads to wobbling movements in the region ofthe running surfaces which support such a rotary drum on thecorresponding supporting rollers and are formed by riding rings mountedon the corresponding sections of the drum. In order to be able tocompensate for impaired supporting action due to such wobbling movementsof the rotary drum running surfaces and to reduce the resulting abrasion(wear) and damage to the circumferential surfaces or running surfaceswhich are in engagement with one another, numerous embodiments ofsupporting roller sets are already known in which the supporting rollersand/or the bedplates bearing them are supported so as to be tiltable oraxially movable relative to a stationary

In this case it should basically be noted that the irregular supportingaction in the contact surface between two touching cylinders, which hasalready been addressed above, can be caused by a so-called “skewing”and/or by a so-called “edge support”. “Skewing” is understood to meanthe situation where the parallel central axes of two touching cylindersare twisted relative to one another about their common connectingnormal, so that the twisted central axis have no common point ofintersection. In such skewing an irregular pressure distribution occursin the contact surfaces with the maximum in the middle of the contactsurfaces (viewed over the length of the cylinder), and additionally inthe rolling operation between the circumferential surfaces of thecylinders (e.g. between the riding ring of a rotary drum and asupporting roller) the skewing produces axial forces, i.e. forces in thedirection of the cylinder axes, in the contact surfaces whencorresponding opposing forces (e.g. a so-called “slope take-off force”of a rotary kiln which acts axially) are present. “Edge support” isunderstood to mean the situation where the parallel central axes of twotouching cylinders are twisted relative to one another in their commonplane, so that the twisted central axes have a common point ofintersections. In this edge support the so-called “Hertzian pressure” isdistributed irregularly over the contact surfaces on the length of thecylinders, i.e. the resulting pressure from the integration of thesurface pressure (Hertzian pressure) acts unilaterally radially on thetouching cylinders.

In practice attempts are made to prevent the skewing and edge support bythe use of self-adjusting supporting rollers or supporting rollersystems and thus to achieve a favourable contact pattern (constantHertzian pressure) between the rotary drum running surfaces and theouter circumferential surfaces of the supporting rollers as far aspossible in all operating conditions. In order to be able to follow allpossible movements (wobbling etc.) of the running surfaces, the bedplateof a supporting roller would for example have to be mounted so that ithas at least two degrees of freedom in rotation about the theoreticalaxes of the skewing and of the edge support. A spherical bearing wouldof course meet this requirement. However, in such a bearing an unstablemechanical system is produced, i.e. the supporting roller can move in anuncontrolled manner relative to the rotary drum running surface. Thecritical degree of freedom of this self-adjustment is the rotation aboutthe theoretical axis of rotation of the skewing, the skewing of thesupporting roller being caused by eccentric circumferential forces(tractive forces in the case of non-driven supporting rollers anddriving forces in the case of driven supporting rollers). As therotation or skewing increases no restoring forces are produced on thesupporting roller, so that the supporting roller goes out of control.Such a system is not capable of functioning.

In order to avoid the described instability, it is known in the art tomount the bedplate of a self-adjusting supporting roller so that nouncontrollable skewing can occur, i.e. of the two necessary degrees offreedom of the self-adjusting bearing of the bedplate the degree offreedom of the skewing is dispensed with. The remaining degree offreedom prevents the edge support between the rotary drum runningsurface and the supporting roller. The bedplate thus mounted with thefirmly connected supporting roller follows the rotary drum runningsurface (riding ring) through tilting movements only in one directionand thus prevents the said edge support. The position of the theoreticalaxis of rotation about which the tilting movements take place plays asignificant role in the susceptibility of the self-adjustment to axialforces on the part of the rotary drums.

In a construction which is known from EP-A-0 109 136 and correspondsapproximately to the supporting roller set, the supporting roller issupported on its axle via two rotary bearings by the two ends of atiltable bedplate. This bedplate is mounted by means of a centralself-orienting roller bearing essentially in the form of a circularcylindrical part which is in movable contact with the inner face of abearing shell in the form of an annular cylinder segment, the outer faceof which is supported on a horizontal foundation plate. Theself-orienting bearing in the form of a circular cylindrical part andthe bearing shell or the cylinder segment form as an entity the actualself-orienting bearing for the bedplate. Since the inner face of thecylinder segment is equipped with a sliding surface the self-orientingbearing supporting the bedplate can move along the inner sliding surfaceof the cylinder segment, and during this movement the cylinder segmentcarries out a pendulum movement on the foundation. In order that thebedplate and the supporting roller borne by it can carry out an axialdisplacement corresponding to the axial movement of the rotary drumriding ring, mechanical or hydraulic drive means are provided which canbe correspondingly actuated by the riding ring. The two supportingrollers of a supporting roller set can be borne by a common bedplate, aseparate self-orienting bearing being disposed below each roller;however, it is also possible to support each of the supporting rollerson a separate bedplate and then to connect the two bedplates to oneanother by way of clamping cables or clamping rods to absorb expansionforces.

If in the known construction last described (EP-A-0 019 136) the skewingexplained above is to be adjusted, then this is obviously only possibleby a displacement on the bedplate of the rotary bearing supporting thesupporting roller axle. Such a displacement of the rotary bearing of thesupporting roller axle on the bedplate requires relatively highconstruction costs and is only possible with special heavy tools andwith a relatively high consumption of time. If in this knownconstruction two separate bedplates are provided for the two supportingrollers, then the clamping rods or the like must be constructed so as toabsorb relatively high expansion forces and torsional forces.

The object of the invention is to create a supporting roller set whichavoids edge support and at least largely avoids skewing and which withrelatively simple design and reliable operation ensures an optimalself-adjustment with easy action of each supporting roller.

This object is achieved according to the invention by the features setout.

Advantageous embodiments and variants of the invention are the subjectmatter of the subordinate claims.

The invention is based upon the knowledge that a self-adjustingsupporting roller of a supporting roller set must, in addition to havinga stable running, fulfil at least the following requirements:

a) The mounting of the tiltable bedplate must have an easy action sothat the supporting roller can follow the wobbling deflections of therunning surface or of the riding ring of the rotary drum to be supportedwithout high adjusting moments, any remaining edge support beingdetermined by necessary adjusting moments of the bedplate mounting

b) Each self-adjusting supporting roller should not react to forces inthe direction of the supporting roller axis (axial forces), i.e. theaxial forces which are always present should not influence thesupporting action.

c) Unavoidable self-oscillations (every component has self-oscillations)of the self-adjusting supporting rollers should remain unaffected byforces (or their changes over time) in the contact surface between therotary drum running surface and the supporting roller, becauseincitation of self-oscillations by these forces would lead to irregularwear on the outer circumferential surface of the supporting rollers.

Therefore in the supporting roller set according to the invention eachbedplate bearing a supporting roller—when viewed transversely withrespect to the rotary drum and to the supporting rollers—is supported onthe foundation by way of two articulated bearings which are transverselyspaced from one another, of which the inner articulated bearing whichlies nearer to the vertical longitudinal central axis of the rotary drumis constructed in the form of a ball-and-socket bearing and as a fixedbearing is disposed statically on the foundation, whilst the outerarticulated bearing which lies further away from this verticallongitudinal central plane forms a movable bearing and is supported soas to be slidably movable on the foundation approximately in the shapeof an arc of a circle about the central point of the ball of the innerball-and-socket bearing.

This construction according to the invention facilitates optimaleasy-action self-adjustment of each bedplate and thus of the supportingroller borne by this bedplate, wherein the supporting rollers and thebedplates bearing them are stabilised by the running surfaces or ridingrings of the rotary drum which are supported on the outercircumferential surfaces, but in this case due to their easy-actiontiltability (by way of the articulated bearing) and by way of theapproximately arcuate slidably movable support on the foundation theycreate the precondition so that on the one hand an unwanted edge supportis avoided and on the other hand any unwanted skewing of each supportingroller can be stopped quickly and with little work involved by acorresponding sliding movement of the outer articulated bearing on thefoundation.

In this case it is particularly advantageous if an adjusting device isprovided in the region of the outer articulated bearing and acts on thebedplate in such a way that this bedplate is displaceable in thedirection of the arcuate slidably movable support of the outerarticulated bearing relative to the foundation and thus the supportingroller borne by it is adjustable or readjustable in the sense of askewing adjustment relative to the rotary drum running surface.

It is also regarded as advantageous if the two articulated bearings ofthe or of each bedplate are essentially constructed as axial articulatedbearings and if in the normal position of supporting roller and bedplatethe central axis of the inner articulated bearing is oriented so that itis inclined with respect to the horizontal, this inclination beingdetermined by the direction of action of the resultant forces acting onthe appertaining supporting roller, i.e. this inclination or angledposition of the inner ball-and-socket bearing results from the vectorialaddition of circumferential forces (e.g. bearing frictional forces anddriving forces) and bearing forces on the or each supporting roller.

A mere comparison of this previously described construction according tothe invention with last-described known construction (EP-A-0 019 136)makes clear on the one hand the extremely simple and quick possibilityfor adjustment in the case of skewing of the or each supporting roller,i.e. skewing caused for example by axial forces on the part of therotary drum can be eliminated in an extremely simple manner and withlittle consumption of time and energy. On the other hand—in contrast tothe said known construction—due to the design according to the inventionexpansion forces are absorbed by the inner ball-and-socket bearing whichis constructed as a fixed bearing, so that no special elements arenecessary for absorption of torsional forces.

In so afar as the adjusting device for adjustment of the skewing of thesupporting roller is concerned, this can be constructed in aparticularly advantageous and simple manner in that it comprises twoadjusting screws which lie axially spaced opposite one another, aremovable relative to one another and act substantially horizontally, aswell as a stop element, the lateral faces of which form stop or contactsurfaces for the ends of these screws. Thus the skewing adjustment orthe adjustment of each bedplate and of the supporting roller borne by itrelative to the rotary drum running surface can be carried out in anextremely simple manner using a very simple hand tool, for example aspanner, and also quickly and with little force.

The invention will be explained in greater detail below with referenceto the drawings, in which:

FIG. 1 shows a longitudinal view, which has been kept quite schematic,of a longitudinal section of a rotary drum which is rotatably supportedfor example on two supporting roller sets constructed according to theinvention;

FIG. 2 shows a transverse or end view of a supporting roller setaccording to invention, on an enlarged scale and in sectionapproximately in the right-hand half, approximately corresponding to thesection line II—II in FIG. 1;

FIG. 3 shows a side view (approximately corresponding to the arrow IIIin FIG. 2) of a bedplate of the supporting roller set supported by wayof a articulated bearings on a foundation;

FIG. 4 shows a plan view of a bedplate of the supporting roller set;

FIG. 5 shows an enlarged detail approximately corresponding to theportion V in FIG. 3 in order to explain an adjusting device for thebedplate;

FIG. 6 shows a vertical sectional view through an inner ball-and-socketbearing of the bedplate;

FIG. 7 shows a vertical sectional view through an outer ball-and-socketjoint of the bedplate;

FIGS. 8, 9 and 10 shows approximately similar longitudinal side views ofthree different embodiments of the supporting roller set according tothe invention.

First of all, the longitudinal view according to FIG. 1 shows quitegenerally how a rotary drum or a corresponding longitudinal section of arotary drum 1 is rotatably supported on for example two supportingroller sets 2 constructed according to the invention. It may be assumedfor example that this rotary drum 1 is a rotary kiln (withcorrespondingly large dimensions in terms of diameter and length) whichcan be driven in rotation about its longitudinal axis 1 a in a mannerwhich is known per se and is therefore not illustrated in greaterdetail. Each supporting roller set 2 can be constructed in substantiallythe same way, so that in the following description only one of themneeds to be explained in detail.

An additional look at the transverse or end view according to FIG. 2makes it clear that the (each) supporting roller set 2 contains twosupporting rollers 3 which lie in pairs symmetrically on both sides of avertical longitudinal plane 1 b of the rotary drum 1 which extendsthrough the longitudinal axis 1 a, a corresponding running surface ofthe rotary drum 1 being rotatably supported on the outer circumferentialsurface or running surface 3 a of each of the said rollers, and thisrotary drum running surface is generally formed by a correspondinglyreinforced shell portion of the rotary drum 1, but preferably—as in thisexample—a respective riding ring 4 (or the outer circumferential surfaceor running surface thereof) mounted in a manner which is known per se onthe outer circumference of the rotary drum 1. The widths of thesupporting rollers 3 extending in the axial direction and of the ridingrings 4 are adapted to one another in the usual way. Each supportingroller 3 is freely rotatably mounted by way of its supporting rolleraxle 3 b in two rotary bearings (usual plain bearings or self-orientingroller bearings). This mounting of the supporting roller axles 3 b inthe rotary bearings 5 can advantageously be floating in a manner whichis known per se, so that the supporting roller 3 which is non-rotatablyborne by the supporting roller axle can to a limited extent follow axialmovements of the rotary drum 1 and riding rings 4 which occur duringoperation; this limited—floating axial movability of the supportingrollers 3 and supporting roller axles 3 b can be used in the usualway—for example by means of thrust washers—for visual checking, so thatin the event of axial forces occurring and causing skewing acorresponding adjusting device can be actuated for elimination of theskewing, and this will be discussed in greater detail below.

Each supporting roller axle 3 b and the appertaining supporting roller 3is fixed by way of its two rotary bearings 5 on a bedplate 6 which inturn is tiltably supported on a static foundation or foundation base 7.In the illustrated embodiment each supporting roller 3 of a supportingroller set 2 is disposed on a separate bedplate 6, the two bedplates 6of the supporting roller set 2 being supported on a common base frame(or a common base plate 8) which in turn is statically disposed on theactual foundation 7, i.e. the common base frame 8 forms a or the part ofa static foundation on which the bedplates 6 are directly supported,although the foundation base 7 may also be constructed so that thebedplates 6 could be directly be supported thereon.

A significant idea concerning this (each) supporting roller set 2 is tobe seen in the fact that each bedplate 6 (and thus also the supportingroller 3 borne by it)—when viewed transversely with respect to therotary drum 1 and to the supporting rollers 3, that is to saycorresponding to the view according to FIG. 2—is supported on the baseframe 8 (and thus also on the static foundation 7) by way of twoarticulated bearings 9, 10 which are disposed at a corresponding axialspacing QA from one another and which in the illustration according toFIG. 2 are to be seen only in the region below the right-hand bedplate 6(as this is a partial sectional view), whilst in the left-hand half ofFIG. 2 they are hidden (as this purely an end view). Of thesearticulated bearings 9, 10, the articulated bearing 9 which lies closerto the vertical longitudinal central axis 1 b of the rotary drum 1 isconstructed in the form of a ball-and-socket bearing and in this case isdisposed as a fixed bearing statically on the base frame 8 (but alsodirectly on the foundation base 7 if need be). By contrast, the outerarticulated bearing 10 which lies further away from this verticallongitudinal central plane 1 b forms a movable bearing, and in this casethis outer articulated bearing 10 is supported on the base frame 8 so asto be slidably movable on the foundation approximately in the shape ofan arc of a circle about the central point 9 a of the innerball-and-socket bearing 9, as is indicated by the arcuate double arrow11 in the plan view according to FIG. 4 of the bedplate 6.

In the right-hand half in FIG. 2 it can also be seen that a straightline 12 connecting the points of articulation 9 a, 10 a of the innerarticulated bearing 9 and of the outer articulated bearing 10 forms atransversely extending geometric pivot axis which in turn forms a commonaxis of tilt for these two articulated bearings 9, 10 and preferablyextends substantially approximately horizontally. In this case theappertaining supporting roller together with the bedplate 6 which bearsit is then accordingly supported so that it is tiltable about this axisof tilt 12, i.e. according to FIG. 2, right-hand half, perpendicular tothe drawing plane and according to FIG. 3 in the direction of the doublearrow 13.

An adjusting device 14 is also of particular importance which isprovided in the region of the outer articulated bearing 10 (cf FIGS. 3and 5) and acts on the or each bedplate 6 in such a way that thisbedplate 6 can be displaced in the direction of the aforementionedarcuate slidably movable support (double arrow 11) of the outerarticulated bearing 10 relative to the static foundation 7 or the baseframe 8, as a result of which the supporting roller 3 borne by it can beprecisely adjusted in the sense of a skewing adjustment relative to therunning surface or to the riding ring 4 of the rotary drum 1.

As can be seen in the enlarged detail view according to FIG. 5, forskewing adjustment of the supporting roller 3 (by way of theappertaining bedplate 6) the adjusting device 14 comprises two adjustingscrews 15 which lie axially spaced opposite one another, are movablerelative to one another and act substantially horizontally, as well as astop element 16 which is disposed between the opposing ends 15 a ofthese adjusting screws, the lateral faces 16 a, 16 b of the stop elementforming stop or contact surfaces for the ends 15 a of these screws. Inthis case it is regarded as advantageous if the two adjusting screws 15are fixed (for example welded) on the underside 6 a of the bedplate 6approximately in the region of the outer articulated bearing 10, whilstthe stop element 16 is firmly mounted in an approximately uprightposition on the base frame (as shown in FIG. 5) and in this case extendsfreely with its upper end 16 c sufficiently far into the region betweenthe two ends of the adjusting screws 15 a, whilst still maintainingsufficient spacing from the underside 6 a of the bedplate, so thatduring the tilting movement of the bedplate 6 it cannot come intocontact with this underside 6 a.

Whilst the inner articulated bearing 9 of each bedplate 6 is always—asmentioned—constructed in the form of a ball-and-socket bearing, theouter articulated bearing 10 can generally be constructed in anysuitable manner which allows a pivotability in a pivot plane 10 b lyingparallel to the vertical longitudinal central plane 3 c of thesupporting roller 3 For this purpose the outer articulated bearing 10could be construction approximately in the form of a simple hingebearing (pivot hinge bearing). However, in the present embodiment it ispreferred that the outer articulated bearing 10 of the/each bedplate 6should be constructed in the form of a ball-and-socket bearing(substantially the same as the inner articulated bearing 9).

In so far as the construction and arrangement of the two articulatedbearings 9, 10 in the region between the appertaining bedplate 6 andbase frame 8 is concerned, both articulated bearings 9, 10 of eachbedplate 6 are constructed on the one hand as ball-and-socket bearings(as mentioned) and on the other hand essentially as axial articulatedbearings. The latter is possible due to the fact that in the starting ornormal position—substantially shown in the drawings—of the supportingroller 3 and bedplate 6 the central axis 10 c of the outer articulatedbearing 10 which passes through the central point 10 a of the ball isoriented substantially vertically (cf in particular FIGS. 3 and 7). Bycontrast, the central axis 9 c of the inner articulated bearing 9 isoriented at an inclination α with respect to the horizontal H, as can beseen from FIGS. 3 and 6. This angled position or inclination α isdetermined by the direction of action of the resultant forces acting onthe appertaining supporting roller 3, i.e. from the vectorial addition(e.g. bearing frictional forces and optionally driving forces) as wellas bearing forces. This makes possible the construction of the twoarticulated bearings 9, 10 of each bedplate 6 as axial articulatedbearings, which brings with it a particularly simple and thereforeinexpensive design of these articulated bearings 9, 10, which becomesparticularly clear when one considers that with another orientation andarrangement these articulated bearings would also have to absorbadditional radial loads, which would involve a correspondingly moreexpensive articulated bearing design. It should be mentioned, however,that the use of articulated bearings which can be loaded axially andradially is not fundamentally excluded in this design according to theinvention.

It can also be seen in FIG. 3 that the central point 9 a of the innerball-and-socket bearing 9 is disposed vertically below the contact line17 between the outer circumferential surface—running surface 3 a of thesupporting roller 3 and the running surface/riding ring 4 of the rotarydrum 1. This has the advantage that axial forces on the supportingroller 3 (and correspondingly also on the bedplate 6) caused by an axialmovement of the rotary drum 1 cannot exert any influence on theadjusting means 14 for the skewing of the supporting roller 3.

The design of the two ball-and-socket bearings 9 and 10 is shown ingreater detail in FIGS. 6 and 7. First of all it can be generally seenhere that both ball-and socket bearings 9, 10 are of substantially thesame construction. Accordingly each ball-and-socket bearing 9, 10 ispreferably constructed in the form of a spherical segment bearing.

Considering first of all the design of the inner ball-and-socket bearing9 according to FIG. 6, then this ball-and-socket bearing (sphericalsegment bearing 9) has a first spherical segment part 9.1 which with aconvex outer plain bearing surface 9.2 in the shape of a sphericalsegment is mounted so as to be capable of universal swivelling movementin a concave inner plain bearing surface 9.3., which is in the shape ofa spherical segment and like a joint seat, of a second spherical segmentpart 9.4. These two spherical segment parts 9.1 and 9.4 are ofapproximately circular construction—as FIG. 6 shows clearly—and thefirst spherical segment part 9.1 is firmly mounted on a type of axlejournal 18 which is in turn fixed on a projection 6 b of the bedplate 6which is oriented correspondingly obliquely downwards. The secondspherical segment part 9.4 on the other hand is mounted or supportedstatically—for example by way of a connecting part 9.5—on a fixingprojection 8 a of the base frame which is oriented correspondinglyobliquely upwards.

Also the outer ball-and-socket bearing (spherical segment bearing) 10has a first spherical segment part 10.1 which with a convex outer plainbearing surface 10.2 in the shape of a spherical segment is mounted soas to be capable of universal swivelling movement in a concave innerplain bearing surface 10.3, which is in the shape of a spherical segmentand like a joint seat, of a second spherical segment part 10.4. Also inthis outer ball-and-socket bearing (spherical segment bearing) 10 thetwo spherical segment parts 10.1 and 10.4 are of circularconstruction—as can be seen from FIG. 7 However, the second sphericalsegment part 10.4 of this outer ball-and socket bearing 10 is supportedon the base frame 8 not so as to be fixed (as in the case of the innerball-and-socket bearing 9) but so as to be slidably movable in thedirection of the double arrow 11 (FIG. 4) This slidably movable supportcould take place in the simplest form in that connecting part 10.5 whichfirmly receives the spherical segment part 10.4 is supported with itsunderside 10.5 a directly on a corresponding opposing surfaceconstructed as a sliding abutment on the upper face of the base frame 8.However, according to the embodiment illustrated in FIG. 7 it ispreferred that in the region below the connecting part 10.5 a planarapproximately plate-like sliding abutment 20 is fixed—optionallyreplaceably—separately on the upper face of the base frame 8, and theunderside 10.5 a of the connecting part 10.5 likewise constructed as asliding surface and thus the lower second spherical segment part 10.4 issupported so as to be slidably movable on the upper face 20 a,constructed as a sliding surface, of the sliding abutment. Thus eachsliding abutment 20 is constructed in the form of a substantially flatplain bearing plate. This sliding abutment or this plain bearing plate20 is advantageously produced from a sliding material with relativelylow coefficients of friction, e.g. from grey-cast iron or correspondingplastic material.

In the previously described supporting roller set 2 according to theinvention each supporting roller 3 is constructed and disposed in anoptimal manner so that it is self-adjusting relative to the appertainingriding ring of the rotary drum 1. Since these self-adjusting supportingrollers 3 react negatively to axial forces, they should not have anyskewing. For this reason it is advantageous to be able to check theposition of the supporting rollers 3 and their supporting roller axles 3b at least visually—as already mentioned above—so that in the event thatskewing of the supporting roller occurs this skewing can be quicklyeliminated with the aid of the adjusting device 14 in order to be ableto adjust the corresponding supporting roller 3 as far as possiblewithout skewing. In this case repeated adjustment of the skewing may benecessary due to changed operating conditions of the rotary drum 1 anddue to other influences. The actuation of the described adjusting device14 for adjustment of the skewing of the supporting rollers has arelatively easy action and is simple. If the illustration particularlyin FIG. 5 is considered again in this respect, then the adjusting screws15 can be constructed as simple hexagonal screws and can be secured intheir adjusted position by corresponding lock nuts (as illustrated).Thus these adjusting screws 15 can be actuated quickly and withoutspecial cost with the aid of a suitable spanner.

As is known per se in the art, the supporting rollers 3 of supportingroller sets 2 for rotary drums 1 can be constructed merely as bearing orsupporting rollers or also as drivable supporting rollers. Examples ofthese are explained below with reference to the embodiment according tothe invention of a supporting roller set as shown in FIGS. 8, 9 and 10.

From the previous explanations of the construction according to theinvention of the or each supporting roller set 2 and also from thecorresponding previous figures of the drawings it is already basicallyapparent that the central axes 9 c, 10 c (or their corresponding uppercentral portions) of the upper articulated bearing parts which aretiltable together with the appertaining bedplate 6, that is to say thefirst spherical segment parts 9.1 and 10.1, of both articulated bearings9, 10 lie in a common reference plane which extends perpendicular to thebedplate 6 and is oriented at right angles to the vertical longitudinalcentral plane 3 c (FIG. 2) of the appertaining supporting roller 3.

If in this case each supporting roller 3 is constructed corresponding tothe representation in FIG. 8 as a mere support bearing roller, then theappertaining supporting roller axle 3 b is mounted with its ends in thetwo rotary bearings 5 which are disposed on both sides of thesymmetrical vertical transverse central plane 3 d of the supportingroller. In this construction (FIG. 8) of the supporting roller 3 theabove-mentioned reference plane 21 for the upper articulated bearingparts 9.1, 10.1 of the articulated bearings 9, 10 coincides with thesymmetrical vertical transverse central plane 3 d of the supportingroller 3, because the supporting roller 3 with the supporting rolleraxle 3 b, the two rotary bearings 5, the bedplate 6 and the articulatedbearings 9, 10 form an equilibrium system with respect to the transversecentral plane 3 d

The embodiment illustrated in FIG. 9 operates in principle in a similarmanner, in that a supporting roller 3 is constructed so as to bedrivable, and flanged on to the two ends 3 b ₁ and 3 b ₂ of thissupporting roller 3 is a reduction drive motor 22, 23 which ispreferably a hydraulic motor in each case but can basically be acorresponding electric motor. The difference between this embodimentaccording to FIG. 9 and the embodiment according to FIG. 8 merelyresides in the fact that a similar drive motor 22, 23 is mounted on bothends of the supporting roller, so that here too an equilibrium system isproduced on both sides of the symmetrical vertical transverse centralplane 3 d of the supporting roller. As a result the reference plane 21explained above can again coincide with the previously mentionedtransverse central plane 3 d of the supporting roller 3. Not only in theexample according to FIG. 8 but also in the example according to FIG. 9constructions are therefore produced which are structurally symmetricaland which are easy to manage with regard to torques and tilting momentswhich occur.

The embodiment according to FIG. 10 differs from those according toFIGS. 8 and 9 in that in an otherwise identical construction a reductiondrive motor 22 is flanged on only at one end 3 b, of the supportingroller; therefore the supporting roller 3 is likewise constructed so asto be drivable. Since in this embodiment (FIG. 10) to a certain extent adisequilibrium is produced with regard to the symmetrical verticaltransverse central plane 3 d of the supporting roller 3 due to theunilateral motor drive, a corresponding balancing must be ensured inview of the tiltable support of the bedplate 6 (by way of thearticulated bearings 9., 10 on the base frame 8). For this reason inthis third embodiment (FIG. 10) the reference plane 21 containing thecentral axes of the upper articulated bearing parts of both articulatedbearings 9, 10 is displaced parallel to the symmetrical verticaltransverse central plane 3 d of the supporting roller 3 by a balancingdistance A.

What is claimed is:
 1. Supporting roller set for tiltable, axiallymovable and rotatable support for a rotary drum (1) which can be drivenin rotation, which contains two supporting rollers (3) which liesymmetrically on both sides of a vertical longitudinal central plane (1b) of the rotary drum (1), a running surface (4) of the rotary drum (1)being rotatably supported and on the outer circumferential surfaces (3a) of the said supporting rollers, wherein each of these supportingrollers is freely rotatably mounted by way of its supporting roller axle(3 b) in two rotary bearings (5) which are fixed bedplate (6) tiltablysupported on a static foundation (7, 8), characterised in that eachbedplate (6) bearing a supporting roller (3)—when viewed transverselywith respect to the rotary drum (1) and to the supporting rollers (3)—issupported on the foundation (7, 8) by way of two articulated bearings(9, 10) which are transversely spaced (QA) from one another, of whichthe inner articulated bearing (9) which lies nearer to the verticallongitudinal central axis (1 b) of the rotary drum (1) is constructed inthe form of a ball-and-socket bearing and as a fixed bearing issupported statically on the foundation (7, 8), whilst the outerarticulated bearing (10) which lies further away from this verticallongitudinal central plane (1 b) forms a movable bearing and issupported so as to be slidably movable on the foundation (7, 8)approximately in the shape of an arc of a circle about the central point(9) of the ball of the inner ball-and-socket bearing (9).
 2. Supportingroller set as claimed in claim 1, characterised in that an adjustingdevice (14) is provided in the region of the outer articulated bearing(10) and acts on the bedplate (6) in such a way that this bedplate isdisplaceable in the direction of the arcuate slidably movable support ofthe outer articulated bearing (10) relative to the foundation (7, 8) andthus the supporting roller (3) borne by it is adjustable in the sense ofa skewing adjustment relative to the rotary drum running surface (4). 3.Supporting roller set as claimed in claim 2, characterised in that theadjusting device (14) for adjustment of the skewing of the supportingroller (3) comprises two adjusting screws (15) which lie axially spacedopposite one another, are movable relative to one another and actsubstantially horizontally, as well as a stop element (16), the lateralfaces (16 a, 16 b) of which form stop surfaces for the ends (15 a) ofthese screws.
 4. Supporting roller set as claimed in claim 3,characterised in that the adjusting screws (15) are fixed on theunderside (6 a) of the bedplate (6) approximately in the region of theouter articulated bearing (10), whilst the stop element (16) is firmlymounted in an approximately upright position on the foundation (7, 8)and protrudes freely with its upper end (16 c) into the region betweenthe ends (15 a) of the two adjusting screws.
 5. Supporting roller set asclaimed in claim 1, characterised in that the outer articulated bearing(10) of the bedplate (6) is also constructed in the form of aball-and-socket bearing.
 6. Supporting roller set as claimed in claim 1,characterised in that the outer articulated bearing (10) of the bedplate(6) is constructed approximately in the form of a hinge bearing which ispivotable in a pivot plane (10 b) lying parallel to the verticallongitudinal central plane (3 c) of the supporting roller (3). 7.Supporting roller set as claimed in claim 1, characterised in that astraight line 1(2) connecting the central points of articulation (9 a,10 a) of the inner and outer articulated bearings (9, 10) forms ageometric pivot axis as a common axis of tilt (12) for these articulatedbearings, whereby the appertaining supporting roller (3) together withthe bedplate (6) which bears it is tiltable about this axis of tilt(12).
 8. Supporting roller set as claimed in claim 7, characterised inthat the axis of tilt (12) extends substantially horizontally. 9.Supporting roller set as claimed in claim 7, characterised in that eachball-and-socket bearing (9, 10) is constructed in the form of aspherical segment bearing and has a first spherical segment part (9.1,10.1) which with a convex outer plain bearing surface (9.2, 10.2) in theshape of a spherical segment is mounted so as to be capable of universalswivelling movement in a concave inner plain bearing surface (9.3,10.3), which is in the shape of a spherical segment and like a jointseat, of a second spherical segment part (9.4, 10.4).
 10. Supportingroller set as claimed in claim 9, characterised in that the twospherical segment parts (9.1, 9.4, 10.1, 10.4) of each ball-and-socketbearing (9, 10) are of approximately circular construction, whereby ineach case one spherical segment part (9.1, 10.1) is firmly connected tothe movable bedplate (6) and second spherical segment part (9.4, 10.4)is supported on the foundation (7, 8).
 11. Supporting roller set asclaimed in claim 10, characterised in that the second spherical segmentpart (9.4) of the inner ball-and-socket bearing (9) is firmly connectedto the foundation (7, 8), whilst the second spherical segment part(10.4) of the outer ball-and-socket bearing (10) is supported by asliding surface (10.5 a) so as to be slidably movable on a planarsliding abutment (20) firmly connected to the foundation.
 12. Supportingroller set as claimed in at least one of claim 1, characterised in thatboth articulated bearings (9, 10) of the bedplate (6) are constructedsubstantially as axial articulated bearings and that in the normalposition of the supporting roller (3) and bedplate (6) the central axis(10 c) of the outer articulated bearing (10) is oriented substantiallyvertically and the central axis (9 c) of the inner articulated bearing(9) is oriented at an inclination (α) with respect to the horizontal(H), this inclination (α) being determined by the direction of action ofthe resultant forces acting on the appertaining supporting roller (3).13. Supporting roller set as claimed in claim 12, characterised in thatthe central point (9 a) of the inner ball-and-socket bearing (9) isdisposed vertically below the contact line (17) between the outercircumferential surface (3 a) of the supporting roller (3) and therunning surface (4) of the rotary drum (1).
 14. Supporting roller set asclaimed in claim 1, characterised in that the central axes of the upperarticulated bearing parts (9.1, 10.1) which are tiltable together withthe bedplate (6) of both articulated bearings (9, 10) lie in a commonreference plane (21) which extends perpendicular to the bedplate (6) andis oriented at right angles to the vertical longitudinal central plane(3 c) of the appertaining supporting roller (3).
 15. Supporting rollerset as claimed in claim 14, characterised in that in the case of eachsupporting roller (3) constructed purely as a support bearing roller thereference plane (21) coincides with the symmetrical transverse centralplane (3 d) of the supporting roller (3).
 16. Supporting roller set asclaimed in claim 14, characterised in that at least one supportingroller (3) is constructed so as to be drivable, a reduction drive motor(22, 23) is flanged on to the two ends (3 b ₁, 3 b ₂) of this supportingroller, and in this case the reference plane (21) is oriented so as tocoincide with the symmetrical transverse central plane of the supportingroller.
 17. Supporting roller set as claimed in claim 14, characterisedin that at least one supporting roller (3) is constructed so as to bedrivable and a reduction drive motor (22) is flanged on only at one end(3 b ₁) of the supporting roller axle (3 b) and that in this case thereference plane (21) is displaced parallel to the symmetrical verticaltransverse central plane (3 d) of the supporting roller (3) by abalancing distance (A).
 18. Supporting roller set as claimed in claim 1,characterised in that each bedplate (6) is supported directly on a baseframe (8) disposed firmly on the actual foundation (7).
 19. Supportingroller set as claimed in claim 18, characterised in that the slidingabutments (20) for the outer articulated bearings (10) are firmlymounted on the base frame (8) in the form of substantially flat plainbearing plates which are produced from a sliding material withrelatively low coefficients of friction.
 20. Supporting roller set asclaimed in claim 18, characterised in that each supporting roller (3) ofthe supporting roller set (2) is disposed on a separate bedplate (6) andboth bedplates (6) are supported on a common base frame (8).